JP2912310B2 - Radio receiver control method and recording medium storing control program for the method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio data system (Radio Data System, hereinafter referred to as "Radio Data System").
The present invention relates to a method for controlling a radio receiver having a function (referred to as RDS) and a recording medium on which a control program for the method is recorded.

[0002]

2. Description of the Related Art In a radio receiver having an RDS function,
AF list in data transmitted by RDS (frequency list of stations belonging to the same broadcast network that can be received in multiple regions)
And a PI code (broadcasting station identification code) are recorded in a memory area connected to the inside or outside of the microcomputer,
The automatic tracking function of the broadcasting station is realized by using these stored data.

This automatic tracking function is composed of the following two processing blocks. First, the first processing block is AF
This is a list reception frequency check, in which each frequency of the recorded AF list is tuned with a very short mute, and after receiving the reception state, the process of immediately retuning to the original reception frequency is performed at an appropriate time interval. Is repeated for all the frequencies in the AF list, and the reception state is recorded in association with each frequency. The second processing block is a reception frequency switching check. In the order of the best reception state stored in the AF list reception state check, the P
The I code is acquired, the received frequency is compared with a PI code that stores the received frequency, and the received frequency is switched. In order to obtain the PI code, it is necessary to tune to the target frequency, so mute is applied. However, since the acquisition of the PI code usually requires 10 times or more time than the reception state acquisition, the mute at this time is It is longer than the mute applied in the first processing block.

Conventionally, as a method of realizing the automatic tracking function of the same program broadcasting station, there are two methods for combining the above-mentioned two processing blocks. First, the first method is a method of performing an AF list reception state check irrespective of the reception state of the reception frequency, and performing a reception frequency switching check when there is a frequency having a reception state better than the reception frequency. In the second method, nothing is performed while the reception state of the reception frequency is good, and if it is determined that the reception state has deteriorated due to a predetermined condition, the AF list reception state check and the reception frequency switching check are performed. This is a continuous method. In the case of the first method, since the mute is applied periodically even for a very short time, intermittent sound interruption occurs, and a long mute is applied when the PI code is checked. Deterioration and discomfort in hearing become problems. In the case of the second method, since the mute is concentrated when the automatic tracking function is started, there is the same problem as in the first method.

[0005] In either method, the reception state of the reception frequency is determined by using a method of determining whether the reception state is higher or lower than a predetermined level over a predetermined time width. The receiving frequency is switched regardless of the radio wave condition. For example, in an urban area with many high-rise buildings, an obstacle 23 such as a building enters between the car 21 and the broadcasting station 22 as shown in FIG. 6, and the reception state of the reception frequency temporarily deteriorates. There is. In this case, if the car 21 moves from the shadow of the obstacle 23, the reception state is recovered. However, especially when the car 21 is traveling at a low speed, the automatic tracking function is performed at a predetermined time, Frequent switching of the reception frequency occurs, such as frequent occurrence of check mute or once switching to another frequency having a relatively poor reception state, and then immediately switching back to the original frequency.

This situation will be described in detail for the first method with reference to the drawings. FIG. 7 is a flowchart showing this method. First, a time interval T1 used in the AF list reception state check is initialized with a predetermined value t (step S1), and after the elapse of the time T1 (step S1).
2), mute (step S3), tune to the frequency of the i-th AF list (the initial value of i is 1) (step S4), detect the electric field intensity (step S5), and (Step S6), and it is checked whether or not the checking of the frequencies of all the AF lists has been completed (step S7). If the checking has not been completed, the frequency is retuned to the original receiving frequency. (Step S10), the mute is turned off (Step S9).

After that, i is incremented by i = i + 1 (step S8), and the process returns to step S2 to repeat the subsequent processing. If the check has been completed for all the AF list frequencies, it is checked whether or not there is an AF list frequency whose stored electric field strength is higher than the electric field strength of the reception frequency (step S11). If not, it tunes back to the original reception frequency (step S16), turns off the mute, and ends the process (step S17). If there is, the frequency is tuned to the frequency (step S12), and P
The I code is fetched (step S13). After a while
PI code of received reception frequency and captured PI
The codes are compared (step S14), and if they are the same, the frequency is set as the reception frequency (step S18), the mute is turned off, and the process ends (step S19). If not, the stored electric field strength is set to 0 (step S
15) Return to step S11 and repeat the subsequent processing.

A method of always checking the reception status of the AF list in the first method and reducing the deterioration of sound quality and the unpleasant sensation due to the periodic muting is described in, for example, JP-A-3-148923. Are listed. According to this, instead of setting the time predetermined in step S1 to T1, the vehicle speed is detected as shown in FIG. 8 (step S100), and a time interval corresponding to the vehicle speed is set from the table. A process for determining the check interval time and setting it to T1 (step S101) is added. If the vehicle speed is high and sound cutoff is difficult to notice due to engine sound or the like, the check interval of the AF list reception state check process is shortened, and the vehicle speed is reduced. When is slow, the check interval is lengthened to reduce sound quality deterioration and unpleasant sensation during the AF list reception state check processing.
However, according to this method, the switching of the reception frequency is performed when the check of the reception state of all the frequencies in the AF list is completed. Therefore, the switching frequency of the reception frequency cannot be dealt with by this method. Note that, in FIG. 8, the processing after step S102 is the same as the processing after step S2 in FIG. 7, and thus redundant description will be omitted.

FIG. 9 is a flowchart of a program of the second method. In this second method, AF
The frequency of the list is not checked, and only the reception state of the reception frequency is constantly monitored (step S201), and it is determined whether or not to activate the automatic tracking function based on the reception state within a predetermined time (step S201). S202). Thereafter, the mute is applied (step S203), the frequency is tuned to the i-th frequency (the initial value of i is 1) in the AF list (step S204), and the electric field intensity is detected (step S20).
5) The electric field strength is stored in association with the frequency (step S206). Next, it is determined whether the check of all the frequencies in the AF list has been completed (step S207),
If it has not been finished, it is retuned to the original reception frequency (step S211), and the mute is turned off (step S2).
210), i is incremented by i = i + 1 (step S2)
09), after a predetermined time has elapsed (1 second in this example) (step S208), the flow returns to step S203, and the subsequent processing is repeated.

On the other hand, if the check of the reception status has been completed for all the frequencies of the AF list, it is checked whether there is an AF list frequency whose stored intensity is higher than the electric field intensity of the reception frequency ( Step S21
2). If not, the frequency is retuned to the original reception frequency (step S217), the mute is turned off, and the process is terminated (step S218). If there is, the frequency is tuned to the frequency (step S213), and the PI code is fetched (step S214). Thereafter, the stored PI code of the reception frequency is compared with the fetched PI code (step S215), and if they are the same, the frequency is set as the reception frequency (step S219), the mute is turned off, and the process is terminated (step S219). Step S220). If not, the recorded electric field intensity is set to 0 (step S216), and the process returns to step S212 to repeat the subsequent processing.

In the second method, it is necessary to switch the receiving frequency in a short time after the automatic tracking function is activated, and the time in step S208 cannot be lengthened. Adjusting the electric field strength check interval does not reduce the uncomfortable feeling of hearing. Note that the electric field strength and R
In many cases, the decoding state of DS data is used.

[0012]

The conventional method of controlling a radio receiver is implemented as described above. In the first method, the timing of switching the reception frequency is determined by the electric field of the frequency of all AF lists. When the strength check is completed, for example, when there is only one frequency in the AF list, the reception frequency is frequently switched, and the criterion for selecting the switching destination frequency is
Since the station is set to be stronger than the electric field strength of the receiving frequency, even if the receiving condition of the receiving frequency deteriorates for a very short time, the frequency is switched to a frequency having a lower receiving condition than the receiving frequency, and as a result, unnecessary switching of the receiving frequency is performed. As a result, there is a problem that a sense of incongruity is generated in the hearing, and a switch to another frequency having a poor reception state occurs.

Further, in the case of the second method, since the reception state of the reception frequency is determined in a predetermined time width, the automatic tracking function is executed regardless of the radio wave state around the vehicle. Even if the reception condition deteriorates temporarily within a predetermined time interval, the automatic tracking function is executed, so in this case too, unnecessary switching of the reception frequency will be performed, causing a sense of incongruity in the auditory sense or an appropriate However, there has been a problem that a proper reception state cannot be continuously obtained.

According to the present invention, there is provided a method for checking an AF list reception state irrespective of a reception state and switching to a frequency having a good reception state. In both methods of continuously checking the state and switching the reception frequency, control of the radio receiver that can reduce sound quality deterioration due to muting and discomfort in the sense of hearing, and can eliminate unnecessary reception frequency switching. It is an object to obtain a recording medium on which a method and a control program thereof are recorded.

[0015]

To SUMMARY OF THE INVENTION To achieve the above object, a control method for a radio receiver according to the invention of claim 1 is mounted on a vehicle, the data transmitted RDS
Microcomputer with AF list and PI code
In the memory area connected to the inside or outside of the
Using the stored data, the same
Radio receiver with RDS function for automatic tracking of broadcasting stations
In the control method of the transceiver, the average vehicle speed is calculated, and this average
Set the reception frequency switching time corresponding to the vehicle speed to the reception frequency
A first step of determining from the switching time table;
Check the electric field strength against the frequencies of all broadcasting stations on the F list.
Second to store the electric field strength in association with the frequency
Steps and broadcasts while receiving programs in these frequencies
Check if there is one with a higher electric field strength than the transmitting station.
A third step of determining from the stored electric field strength;
In this third step, the program is larger than the broadcasting station currently receiving the program.
It is determined that there is a frequency with a strong electric field strength and
Times after it is determined to be no in the third step, or
Elapsed time since the last broadcast station change
When switching the reception frequency determined in the first step
Only in the second step
P of the station with the highest stored field strength
The PI code of the broadcasting station receiving the program by acquiring the I code
And if they match, the broadcast station receives the program.
And a fourth step of changing the transmission station.
I do.

[0016] According to a second aspect of the present invention, there is provided a method for controlling a radio receiver, comprising the steps of:
AF list and PI code in incoming data
In a memory area connected inside or outside the computer
And then use these stored data to
Equipped with RDS function for automatic tracking of the same large broadcast station
Average vehicle speed in a radio receiver control method
And the reception frequency switching time corresponding to this average vehicle speed
Automatic tracking based on reception frequency switching time table
First step for function activation determination time and program reception
Get the reception status of the broadcasting station in the middle and check if the reception status is good
A second step of determining
Communication state is determined to be no, and
The time elapsed since the reception condition was determined to be good in
Only when it is longer than the dynamic tracking function activation judgment time,
Activate the auto-tracking function, and select from all broadcasting stations in the AF list.
From the broadcasting station receiving the current program
Search for the same broadcast station that has
Third step of changing the broadcasting station that receives the
It is characterized by the following.

[0017] According to the first aspect of the present invention,
Control method for a radio receiver of the other two, wherein the reception frequency switching
The switching time is longer in the middle and low speed range of the average
Is set to be shorter.

According to a fourth aspect of the present invention, there is provided a recording medium storing a control program according to the first aspect of the present invention .
Record the control method of the radio receiver described in paragraph 1.
And features.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 3 is a block diagram showing a radio receiver that realizes the automatic tracking function according to the present invention. In FIG. 1, reference numeral 1 denotes an antenna, and reference numeral 2 denotes an FM tuner pack. The FM tuner pack tunes to a predetermined frequency based on a voltage signal output from a PLL circuit described later to generate an intermediate frequency signal IF. An intermediate frequency amplifier 3 amplifies the intermediate frequency signal output from the FM tuner pack 2 to a predetermined level. 4 is a stereo demodulation circuit (MPX)
And demodulates the intermediate frequency signal input from the intermediate frequency amplifier 3 into a stereo signal. 9 is a mute circuit, 5
Is an amplifier (AMP), and 6 is a speaker, which is driven by the output of the amplifier 5 and outputs sound.

Reference numeral 8 denotes a 57 KHz band-pass filter (BPF), which passes a 57 KHz sub-carrier amplitude-modulated based on the RDS standard. 10 is RDS
The demodulator demodulates the output of the bandpass filter 8 into a digital signal and outputs the digital signal. Reference numeral 13 denotes an RDS decoder, which decodes a digital signal from the RDS demodulator 10 and demodulates error correction included in the data and RDS data such as AF information and PI code while synchronizing each group. 7 is an electric field strength detector,
The signal intensity of the intermediate frequency signal output from the intermediate frequency amplifier 3 is output.

Further, 14 is a vehicle speed sensor for detecting the vehicle speed of the vehicle, 12 is a microcomputer for performing automatic tracking, which will be described later, based on RDS data, electric field strength signal, vehicle speed, etc., and performing digital tuning processing, and 15 is an operation unit. , 11 are PLL circuits for tuning the FM tuner pack 2 to a frequency based on the frequency data input from the microcomputer 12. Also, 12a
In FIG. 4, a check interval table (correspondence table of the vehicle speed and the electric field strength measurement interval of the frequency of the AF list) used for checking the reception state of the frequency of the AF list is stored in advance in the memory area of the microcomputer. As shown, the time is set so as to be shorter as the vehicle speed is faster and longer as the vehicle speed is slower.

12b stores a reception frequency switching time table (correspondence table between the average vehicle speed and the reception frequency switching time) in the memory area of the microcomputer in advance, and as shown in FIG. It is set so that the switching is slowed down and the switching is fast in the high-speed range. The purpose of using the average speed to determine the reception frequency switching time is to remove the effect of a sudden change in vehicle speed due to a traffic signal or the like. For this purpose, it is desirable that the reference time for calculating the average vehicle speed be longer than the stop signal time of the traffic signal.

Next, the procedure for executing automatic tracking using the radio receiver will be described with reference to the flowchart of FIG. First, the microcomputer 12 is connected to the vehicle speed sensor 1.
4 (step S301), and a time interval T1 for checking the electric field strength of the AF list corresponding to the vehicle speed is determined from the measurement interval table 12a (step S302). After calculating the average of the vehicle speeds within the past predetermined time among the vehicle speeds acquired in step S301 (step S303), the reception frequency switching time table 1
2b, the reception frequency switching time T2 is determined (step S304). The elapsed time from the previous check of the electric field strength of the frequency of the AF list is counted by a counter (not shown). When the count value C1 satisfies C1 <T1, the process returns to step S301 and the above-described processes are repeated. If C1 ≧ T1, the count value C1 is cleared (step S305), muting is performed (step S306), tuning is performed to the i-th frequency in the AF list (step S307), and the The electric field strength at this time is acquired (step S308), and the electric field strength is recorded in association with the frequency of the AF list (step S309). Thereafter, it is checked whether or not all the electric field strength checks have been completed for all the frequencies in the AF list (step S310).
Tune to the reception frequency tuned before step S307 (step S313), turn off the mute (step S312), and increment i by i + 1 → i (step S313).
311), returning to step S301, and step S301.
The subsequent processing is repeated.

If the electric field strength check for all the AF lists has been completed even once, every time the electric field strength check for one frequency is completed,
It is checked whether there is a frequency in the AF list having an electric field strength higher than the reception frequency (step S314). If there is no frequency, the count value C2 is cleared and tuning back to the original reception frequency is performed (step S20). ), The mute is turned off (step S321), and the process ends. On the other hand, when there is a frequency with a strong electric field intensity, the count value C2 is compared with the frequency switching time T2 (step S31).
5) If C2 <T2, proceed to step S320,
The processing after step S321 is performed. If C2 ≧ T2, the frequency is tuned to the frequency having the highest electric field strength among the frequencies in the AF list (step S316), and the PI code is acquired from the RDS decoder 13 (step S317).
Thereafter, the PI code of the reception frequency and the step S31
7 is compared with the PI code acquired (Step S31).
8) In the same case, after the frequency tuned in step S316 is set as the reception frequency, the count value C2 is cleared (step S322), the mute is turned off, and the process ends (step S323). If the PI code is different, the stored electric field strength is set to 0 for the frequency tuned in step S316 (step S319), and the
The processing after 314 is repeated.

FIG. 2 is a flowchart showing a procedure for executing automatic tracking according to another embodiment of the present invention. This procedure will be described with reference to FIG. First, the vehicle speed sensor 1
4 (step S401), and among the acquired vehicle speeds, an average of the vehicle speeds within a predetermined time in the past is calculated (step S402). Then, the average speed corresponds to the average speed from the receiver frequency switching time table 12b. The automatic tracking function activation determination time T3 is determined (step S403).
Thereafter, the reception state of the receiver frequency is acquired (step S404). If the reception state is good and the predetermined automatic tracking function activation condition is not satisfied, the count value C3 is cleared, and the processing after step S401 is repeated. If C3 is satisfied, C3 is compared with T3. If C3 <T3, the process returns to step S401 to repeat the subsequent processing, and
If 3 ≧ T3, steps S203 to S211 in FIG.
After executing the processing of steps S406 to S414 similar to the above, it is checked whether or not there is an AF list frequency whose stored electric field strength is higher than the electric field strength of the reception frequency (step S415).

If there is no AF list frequency stronger than the electric field strength of the reception frequency, the frequency is retuned to the original reception frequency (step S420), the mute is turned off, and the process is terminated (step S421). On the other hand, if there is, the frequency is tuned to the frequency (step S416), and the PI code is fetched (step S417). Thereafter, the PI code of the stored reception frequency is compared with the fetched PI code (step S418). If the PI code is the same, the frequency is set as the reception frequency (step S422), the mute is turned off, and the process is terminated. (Step S423).
If not, the stored electric field strength is set to 0 (step S419), and the process returns to step S415 to repeat the subsequent processing.

Therefore, conventionally, the check is repeated at the electric field strength check interval time determined by the vehicle speed detected at a certain point in time. Therefore, even if the vehicle speed changes during the check loop, the check interval does not change. Although the check interval is set short, the check is performed at the interval even if the vehicle speed decreases during the check loop, so that the sense of incongruity in hearing is not reduced. Detected and reflected in the electric field strength check interval time, it is possible to set a check interval according to changes in vehicle speed, so that even at low vehicle speeds, it is possible to reduce discomfort in hearing and to switch unnecessary frequencies. Can be reduced.

In the second method, the frequency switching is delayed in the middle to low speed range of the vehicle speed, so that when the vehicle is shaded by an obstacle and the reception state is temporarily deteriorated, the frequency of the frequency switching is reduced. Can be reduced. For example, as in the conventional case, when the frequency is switched in advance when the reception state deteriorates for 5 seconds, when the car enters the shadow of an obstacle at a low speed and the reception state deteriorates for 1 minute, Up to 12 reception frequency switchings will be performed,
According to the second method, if the reception frequency switching time is set to 1 minute in the middle to low speed range, the frequency switching is not performed once.

[0029] Even when the distance from the broadcasting station increases and the reception condition deteriorates and the frequency needs to be changed, the change of the reception condition is slow in the middle and low speed range, and the time for the frequency change is high in the high speed range. Is set shorter,
There is no delay in the original frequency switching timing. As a result, unnecessary switching of frequencies can be reduced, and the frequency of muting by checking the electric field strength of the frequency of the AF list can be reduced.

Further, by recording the above-described control procedure as a control program on a recording medium, it is possible to easily and reliably realize automatic tracking of the same program broadcasting station by using this recording medium. it can.

[0031]

As described above, according to the present invention, the constantly changing vehicle speed is detected and reflected in the electric field strength check interval. Switching can be reduced. In addition, when the vehicle speed is in the middle to low speed range, the frequency switching time is delayed so that when the vehicle is temporarily shaded by an obstacle and the reception state deteriorates, the frequency switching frequency is reduced. It is possible to reduce the frequency of muting by checking the electric field strength of the frequency of the AF list, and it is possible to obtain an effect of reducing a sense of discomfort caused by noise due to the noise.

Further, by recording and saving a control procedure for realizing the method of the present invention as a control program on a recording medium, an automatic tracking of the same program broadcasting station can be easily realized using the recording medium. Can be

[Brief description of the drawings]

FIG. 1 is a flowchart showing a control procedure of a radio receiver according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a control procedure of a radio receiver according to another embodiment of the present invention.

FIG. 3 is a block diagram showing a radio receiver that executes the control procedure of FIGS. 1 and 2;

FIG. 4 is an explanatory diagram showing the contents of a check interval table used in the present invention.

FIG. 5 is an explanatory diagram showing the contents of a reception frequency switching time table used in the present invention.

FIG. 6 is an explanatory diagram showing a reception failure state by a radio receiver.

FIG. 7 is a flowchart showing a control procedure of a conventional radio receiver.

FIG. 8 is a flowchart showing a control procedure of another conventional radio receiver.

FIG. 9 is a flowchart showing a control method of another conventional radio receiver.

[Explanation of symbols]

 12 Microcomputer

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sumiko Nirazawa 1-403-3, Kosugicho, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Within NEC Ic Microcomputer System Co., Ltd. (56) References JP-A-3-148923 (JP, A) JP-A-4-95416 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H04B 1/16 H03J 7/22

Claims (4)

(57) [Claims] An RDS transmission is carried on a vehicle.
The AF list and PI code in the data
In the memory area connected to the inside or outside of the computer.
By using these stored data,
Has the RDS function to automatically track the same broadcast station
Average vehicle speed in a radio receiver control method
And the reception frequency switching time corresponding to this average vehicle speed
The first switch determined from the reception frequency switching time table
Step and the frequency of all the stations in the AF list
Check the field strength and correlate the field strength with the frequency.
The second step of storing and the program in these frequencies
Some stations have a higher electric field strength than the broadcasting station currently receiving
Or not from the stored electric field strength.
In the third step and the third step,
It is determined that there is a frequency with a higher electric field strength than the transmitting station.
And whether or not it was previously determined to be no in the third step
Or after changing the broadcasting station to receive the previous program
The elapsed time of the reception frequency determined in the first step
Only when the number switching time is longer than
Has the highest electric field strength stored in the step
Broadcasting station receiving the program by acquiring the PI code of the broadcasting station
Compare with the PI code of
Changing the broadcast station that receives the program.
A method for controlling a radio receiver. 2. RDS transmission is carried on a vehicle.
The AF list and PI code in the data
In the memory area connected to the inside or outside of the computer.
By using these stored data,
Has the RDS function to automatically track the same broadcast station
Average vehicle speed in a radio receiver control method
And the reception frequency switching time corresponding to this average vehicle speed
Automatic tracking based on reception frequency switching time table
First step for function activation determination time and program reception
Get the reception status of the broadcasting station in the middle and check if the reception status is good
A second step of determining
Communication state is determined to be no, and
The time elapsed since the reception condition was determined to be good in
Only when it is longer than the dynamic tracking function activation judgment time,
Activate the auto-tracking function, and select from all broadcasting stations in the AF list.
A large electric field strength from a broadcast station in receiving a current program from
Search for the same broadcast station that has
Third step of changing the broadcasting station that receives the
A method for controlling a radio receiver. 3. The receiving frequency switching time is determined by the average vehicle speed.
It is set to be long in the middle and low speed range and short in the high speed range.
3. The control method for a radio receiver according to claim 1, wherein: 4. A recording medium in which a control program for a method for controlling a radio receiver according to claim 1 is recorded.